sd-event: restore correct timeout behaviour

src/libsystemd/sd-event/sd-event.c

@@ -2180,6 +2180,7 @@ _public_ int sd_event_run(sd_event *e, uint64_t timeout) {
         unsigned ev_queue_max;
         sd_event_source *p;
         int r, i, m;
+        bool timedout;
 
         assert_return(e, -EINVAL);
         assert_return(!event_pid_changed(e), -ECHILD);
@@ -2226,6 +2227,8 @@ _public_ int sd_event_run(sd_event *e, uint64_t timeout) {
                 goto finish;
         }
 
+        timedout = m == 0;
+
         dual_timestamp_get(&e->timestamp);
         e->timestamp_boottime = now(CLOCK_BOOTTIME);
 
@@ -2278,7 +2281,7 @@ _public_ int sd_event_run(sd_event *e, uint64_t timeout) {
 
         p = event_next_pending(e);
         if (!p) {
-                r = 1;
+                r = !timedout;
                 goto finish;
         }